Keithley 2002 Repair Manual

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1 Routine Maintenance
1.1 Introduction..........................................................................................................................................................1-1
1.2 Line fuse replacement..........................................................................................................................................1-1
1.3 Current fuse replacement .....................................................................................................................................1-2
1.3.1 Front AMPS input fuse ..............................................................................................................................1-2
1.3.2 Rear AMPS input fuse ...............................................................................................................................1-3
1.4 Fan filter cleaning ................................................................................................................................................1-3
1.5 Firmware updates.................................................................................................................................................1-3
2 Troubleshooting
2.1 Introduction .........................................................................................................................................................2-1
2.2 Repair considerations...........................................................................................................................................2-2
2.3 Power-on test........................................................................................................................................................2-2
2.4 Front panel tests ...................................................................................................................................................2-2
2.4.1 KEYS test...................................................................................................................................................2-2
2.4.2 DISPLAY PATTERNS Test......................................................................................................................2-2
2.4.3 Character set test........................................................................................................................................2-3
2.5 Diagnostics...........................................................................................................................................................2-3
2.6 Control register bit patterns..................................................................................................................................2-3
2.6.1 Control register ICs....................................................................................................................................2-3
2.6.2 Normal operation bit patterns ....................................................................................................................2-3
2.7 Display board checks ...........................................................................................................................................2-5
2.8 Power supply checks............................................................................................................................................2-5
2.9 Principles of operation .........................................................................................................................................2-6
2.9.1 Block diagrams ..........................................................................................................................................2-6
2.9.2 Display board circuit theory.....................................................................................................................2-11
2.9.3 Power supply circuit theory .....................................................................................................................2-11
2.10 Built-in test overview.........................................................................................................................................2-12
2.10.1 Using Built-In Test...................................................................................................................................2-15
2.10.2 AUTOMATIC Testing.............................................................................................................................2-15
2.10.3 MANUAL Testing...................................................................................................................................2-15
2.11 Built-In test documentation................................................................................................................................2-17
2.11.1 Memory element tests..............................................................................................................................2-18
2.11.2 Digital I/O tests........................................................................................................................................2-19
2.11.3 IEEE-488 bus tests...................................................................................................................................2-20
2.11.4 Triggers tests............................................................................................................................................2-21
2.11.5 A/D converter tests...................................................................................................................................2-23
2.11.6 Integration tests........................................................................................................................................2-27
2.11.7 A/D multiplexer tests ...............................................................................................................................2-49
2.11.8 Temperature sensor test ...........................................................................................................................2-51
Table of Contents

Keithley 2002 Specifications

General

Resolution	8.5 digits
DC Voltage Accuracy	±0.0006%
Maximum DC Voltage	1000 V
Maximum AC Voltage	750 V
Maximum DC Current	3 A
Maximum AC Current	3 A
Connectivity	GPIB, RS-232
DC Voltage Range	100 mV to 1000 V
AC Voltage Range	100 mV to 750 V
Resistance Range	10 Ω to 1 GΩ
Model	2002
Category	Multimeter
Interface	GPIB, RS-232
AC Current Accuracy	±0.1%
Frequency Range	0.1Hz to 300kHz
Display	VFD
Type	Digital
Power Supply	100-240V AC, 50/60Hz
Current Range (DC)	100 μA to 3 A
Current Accuracy (DC)	±0.01%
Current Range (AC)	100 μA to 3 A
Current Accuracy (AC)	±0.1%
DC Current Range	100 μA to 3 A
AC Current Range	100 μA to 3 A